Technical Field
The present invention relates to a method for controlling a power consumption of a group of a plurality of wind turbines, in particular of a wind park. In addition, the present invention relates to a group of a plurality of wind turbines, in particular of a wind park.
Description of the Related Art
Wind turbines and in particular wind parks are not only energy producers, but can also become major energy consumers. As a rule, this change in characteristic occurs in all wind turbines in a region at the same point in time, since most large energy consumers in a wind turbine must be connected due to weather. This applies in particular to large thermal consumers, which must restore or maintain the operational readiness of the wind turbines. For instance, such consumers may be a blade heater or a generator dryer, to name just two examples. Other consumers may also be considered.
Within some regions, the described circumstances can represent a significant problem for the network operator of the electrical supply network, to which these wind turbines are connected. These significant load flow changes cannot be calculated or predicted or, respectively, are difficult to calculate or predict and therefore must be covered by expensive reserves.
The additional costs that thereby arise are then passed on to the operator of the wind turbines, in particular the wind park.
Usually, wind turbines are self-sufficient in their management and also control the reference power, which can also be referred to as the management of the reference power. Here, reference power is understood to mean the power that the wind turbine draws for the described consumption, or for another consumption not described, thus the power it consumes and does not produce. In this case, there are large thermal consumers, which by necessity must be operated in order to restore or maintain the operational readiness of the wind turbine. What makes this problem more difficult is the fact that, as a rule, in this situation, the wind turbine often cannot produce energy or is not permitted to produce energy.
For example, if the wind turbines of a wind park are operated with blade heating to de-ice the blades, as a rule, all installations will adjust the energy production at the same time and begin the operation of the de-icing. This is mainly due the fact that such an icing of the rotor blades will occur practically simultaneously at the same site. This results in a very large reference power for the wind park, which thus exceeds a maximum allowed or, respectively, negotiated reference power and thereby causes enormous additional costs. Such a maximum allowed or negotiated reference power is a reference power that the wind park can draw from the electrical supply network without cost or without especially high cost, for example in order to start the wind park. Although, in principle, it is possible to draw more power from the electrical supply network than the negotiated reference power, power that thus exceeds the negotiated power is compensated at a very high rate.
A further problem is that energy may possibly be wasted when consuming power. For example if a prolonged dead calm is forecast for a region or a wind park, the blades will not need to be de-iced before there is a prospect of wind. Conversely, all systems can be de-iced at once if wind is forecast, without regard to the reference power. This may result in a high price for the power drawn, but may be justified by the fact that a standstill of the wind turbine when the wind is expected can be avoided. The power drawn can thus quickly be regained where applicable.